Method and Apparatus for Uplink Data Transmission

1. A user equipment (UE) for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus UE to: transmit a first message that indicates a subsequent uplink data transmission; receive, based at least in part on the first message, a second message that indicates a set of demodulation reference signal (DMRS) parameters, wherein the set of DMRS parameters is associated with respective UEs in a group of UEs comprising the UE, and wherein a same resource associated with the group of UEs is used for one or more respective uplink transmissions comprising the first message; and transmit, based at least in part on at least one DMRS parameter of the set of DMRS parameters, the subsequent uplink data transmission.

2. The UE of claim 1, wherein the first message comprises a preamble and physical uplink shared channel (PUSCH) transmission.

3. The UE of claim 1, wherein the at least one DMRS parameter comprises at least one of: a DMRS port; or a DMRS sequence.

4. The UE of claim 1, wherein the second message is received in response to the first message, and wherein the at least one processor is further configured to cause the UE to determine the at least one DMRS parameter based at least in part on a relative position of a response signal in the second message.

5. The UE of claim 1, wherein the second message is received in response to the first message, and wherein the response second message comprises a response signal indicating the at least one DMRS parameter.

6. The UE of claim 1, wherein the second message comprises downlink control information (DCI) scheduling the subsequent uplink data transmission, and wherein the DCI indicates the at least one DMRS parameter.

7. The UE of claim 6, wherein the DCI is specific to the UE.

8. The UE of claim 1, wherein the second message is received in response to the first message, and wherein the second message indicates a DMRS parameter group associated with the UE.

9. The UE of claim 8, wherein the at least one processor is further configured to cause the UE to determine the at least one DMRS parameter from the DMRS parameter group.

10. The UE of claim 1, wherein the second message comprises group downlink control information (DCI) scrambled with a group radio network temporary identifier (RNTI), and wherein the group DCI schedules the subsequent uplink data transmission.

11. The UE of claim 10, wherein the group RNTI is as a same RNTI that is used for DCI scheduling a response message in response to the first message.

12. The UE of claim 10, wherein the group RNTI is determined based at least in part on an RNTI used for DCI scheduling a response message in response to the first message and an offset.

13. A network equipment (NE) for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the NE to: receive a first message that indicates a subsequent uplink data transmission transmit, based at least in part on the first message, a second message that indicates a set of DMRS parameters, wherein the set of DMRS parameters is associated with respective user equipment (UEs) in a group of UEs, and wherein a same resource associated with the group of UEs is used to receive one or more respective uplink transmissions comprising the first message; and receive, based at least in part on at least one DMRS parameter of the set of DMRS parameters, the subsequent uplink data transmission.

14. The NE of claim 13, wherein the first message comprises a preamble and physical uplink shared channel (PUSCH) transmission.

15. The NE of claim 13, wherein the second message is transmitted in response to the first message, and wherein the second message indicates the at least one DMRS parameter based at least in part on a relative position of a response signal in the second message.

16. The NE of claim 13, wherein the second message is transmitted in response to the first message, and wherein the second message comprises a response signal indicating the at least one DMRS parameter.

17. The NE of claim 13, wherein the second message comprises downlink control information (DCI) scheduling the subsequent uplink data transmission, and wherein the DCI indicates the at least one DMRS parameter.

18. The NE of claim 13, wherein the second message is transmitted in response to the first message, and wherein the second message indicates a DMRS parameter group associated with at least one UE in the group of UEs.

19. A method performed by a user equipment (UE), comprising: transmitting first message that indicates a subsequent uplink data transmission; receiving, based at least in part on the first message, a second message that indicates a set of demodulation reference signal (DMRS) parameters, wherein the set of DMRS parameters is associated with respective UEs in a group of UEs comprising the UE, and wherein a same resource associated with the group of UEs is used for one or more respective uplink transmissions comprising the first message; and transmit, based at least in part on at least one DMRS parameter of the set of DMRS parameters, the subsequent uplink data transmission.

20. A processor for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: transmit a first message that indicates a subsequent uplink data transmission; receive, based at least in part on the first message, a second message that indicates a set of demodulation reference signal (DMRS) parameters, wherein the set of DMRS parameters is associated with respective UEs in a group of UEs, and wherein a same resource associated with the group of UEs is used for one or more respective uplink transmissions comprising the first message; and transmit, based at least in part on at least one DMRS parameter of the set of DMRS parameters, the subsequent uplink data transmission.